template<typename color>
class image : public std::vector<color>
{
    public:

    size_t w, h, d;
    float delay; // frame delay, when loading an animation

    image();
    image( size_t w, size_t h, size_t d = 0, const color &filler = color::hsla() );
    explicit image( const std::string &filename, bool mirror_w = false, bool mirror_h = false );
    explicit image( const void *ptr, size_t len, bool mirror_w = false, bool mirror_h = false );

    bool load( const void *ptr, size_t len, bool mirror_w = false, bool mirror_h = false );
    bool load( const std::string &filename, bool mirror_w = false, bool mirror_h = false );

    bool save( const std::string &filename ) const;

    bool save_as_bmp( const std::string &filename ) const;
    bool save_as_dds( const std::string &filename ) const;
    bool save_as_tga( const std::string &filename ) const;
    bool save_as_png( const std::string &filename, unsigned stride = 4 ) const;
    bool save_as_pug( const std::string &filename, unsigned quality = 90 ) const;
    bool save_as_jpg( const std::string &filename, unsigned quality = 90 ) const;
    bool save_as_webp(const std::string &filename, unsigned quality = 90 ) const;
    bool save_as_ktx( const std::string &filename, unsigned quality = 10 ) const;
    bool save_as_pvr( const std::string &filename, unsigned quality = 10 ) const;
    bool save_as_pkm( const std::string &filename, unsigned quality = 10 ) const;

    std::string encode_as_png( unsigned stride = 4 ) const;
    std::string encode_as_pug( unsigned quality = 90 ) const;
    std::string encode_as_jpg( unsigned quality = 90 ) const;
    std::string encode_as_webp(unsigned quality = 90 ) const;
    std::string encode_as_ktx( unsigned quality = 10 ) const;
    std::string encode_as_pvr( unsigned quality = 10 ) const;
    std::string encode_as_pkm( unsigned quality = 10 ) const;

    inline const size_t size() const;
    bool loaded() const;

    inline color &at( size_t offset );
    inline color &at( size_t x, size_t y );
    inline color &at( size_t x, size_t y, size_t z );
    inline color &atf( float x01 );
    inline color &atf( float x01, float y01 );
    inline color &atf( float x01, float y01, float z01 );

    inline const color &at( size_t offset ) const;
    inline const color &at( size_t x, size_t y ) const;
    inline const color &at( size_t x, size_t y, size_t z ) const;
    inline const color &atf( float x01 ) const;
    inline const color &atf( float x01, float y01 ) const;
    inline const color &atf( float x01, float y01, float z01 ) const;

    image copy( size_t ox, size_t oy, size_t w = ~0, size_t h = ~0 ) const;
    image paste( size_t at_x, size_t at_y, const image &other ) const;
    image crop( size_t left, size_t right, size_t top, size_t bottom ) const; // each param is number of row/cols to crop

    image flip_w() const;
    image flip_h() const;
    image rotate_left() const;
    image rotate_right() const;

    image operator *( const color &other ) const;
    image operator /( const color &other ) const;
    image operator +( const color &other ) const;
    image operator -( const color &other ) const;

    image &operator *=( const color &other );
    image &operator /=( const color &other );
    image &operator +=( const color &other );
    image &operator -=( const color &other );

    image to_rgba() const;
    image to_hsla() const;

    image to_premultiplied_alpha() const;
    image to_straight_alpha() const;

    std::vector<unsigned int>  rgba32() const;
    std::vector<unsigned char> rgbx( unsigned char ) const;
    std::vector<unsigned char> bgrx( unsigned char ) const;
    std::vector<unsigned char> rgba() const;
    std::vector<unsigned char> bgra() const;
    std::vector<unsigned char> rgb() const;
    std::vector<unsigned char> bgr() const;
    std::vector<unsigned char> ya() const;
    std::vector<unsigned char> y() const;
};

    spot::image img( filename );

    spot::image saturated = img * spot::hsla( 1, 2, 1, 1 );
    spot::image desaturated = img * spot::hsla( 1, 0.5f, 1, 1 );
    spot::image gray = img * spot::hsla( 1, 0, 1, 1 );
    spot::image light = img * spot::hsla( 1, 1, 1.75f, 1 );
    spot::image hue = img + spot::hsla( 0.5f, 0, 0, 0 );
    spot::image warmer = img + spot::hsla( -0.08f, 0, 0, 0 );
    spot::image colder = img + spot::hsla(  0.08f, 0, 0, 0 );

    img.save_as_bmp("collage.bmp");
    img.save_as_dds("collage.dds");
    img.save_as_jpg("collage.jpg", 80);
    img.save_as_ktx("collage.ktx", 10);
    img.save_as_pkm("collage.pkm", 10);
    img.save_as_png("collage.png");
    img.save_as_pug("collage.pug", 80);
    img.save_as_pvr("collage.pvr", 10);
    img.save_as_webp("collage.webp", 80);